1. Field of the Invention
The present invention relates to a navigation apparatus mounted on a mobile unit such as vehicle for a guide to a movement path, and so forth.
2. Description of the Prior Art
In order to inform a driver of guide information about an intersection on a set travel path, a conventional navigation apparatus outputs guides about a shape of the intersection serving as a guide target and a direction of travel from the guide target intersection through voice.
FIG. 62 is a flowchart showing a flow of processing in such a conventional navigation apparatus disclosed in, for example, JP-A 6/34383. The reference numerals are used for only essential steps in the drawing, and a description will now be given of the operation. In the navigation apparatus, as a first step, a current position pt of a mobile unit is calculated in step ST1. Further, a distance between the front specified point Xi (in front of the mobile unit) and the next specified point Xi+1 is calculated in step ST2. Subsequently, in step ST3, it is decided whether or not the distance between the two points is within a predetermined value. If within the predetermined value, the operation branches to step ST4 to output a guide voice message about the two points. On the other hand, if the distance is equal to or more than the predetermined value, the operation branches to step ST5 to output only a guide voice message about the specified point Xi.
The conventional navigation apparatus has the above structure. Hence, the contents of guide do not include a relationship between the guide target intersections, resulting in a problem of an obscure relationship between the guide target intersections. Besides, there are problems in that the contents of guide are outputted exclusively through the voice, and means for visually displaying the relationship and the contents of guide is not commercially available. In addition, there is another problem in that the guide target intersection can not easily be identified because of an obscure distance from the mobile unit to the guide target intersection.